G-19—Policy on in situ retrofitting of diaphragm meters with an automatic meter reading device and/or replacement register

The copy of this document located on Measurement Canada’s website is considered to be the controlled copy.

Category: Gas
Bulletin: G-19 (rev. 4)
Document(s): Electricity and Gas Inspection Regulations, subsection 3(2)
Issue date:
Effective date:
Supersedes: G-19 (rev. 3)


Table of content


1.0 Purpose

The purpose of this bulletin is to communicate the policy on retrofitting diaphragm gas meters in service with an automatic meter reading (AMR) device and/or replacement register.

2.0 Scope

2.1 This bulletin applies to organizations seeking accreditation to install mechanically coupled AMR devices and/or replacement registers on diaphragm gas meters in service.

2.2 This bulletin also applies to organizations which were previously accredited to install mechanically coupled AMR devices on diaphragm gas meters in service and intend to:

  1. continue installing more AMR devices of the meter/AMR device model combinations for which they were accredited; or
  2. seek an expansion of the scope of their accreditation program to include additional meter/AMR device or meter/register model combinations.

2.3 For the purpose of this bulletin's scope, the application of subsection 3(2) of the Electricity and Gas Inspection Regulations and the scope of accreditation for telemetering installations under the requirements of S-A-01, the term automatic meter reading device and the associated requirements that apply to the installation of AMR devices on diaphragm meters in service shall equally apply to AMR devices, telemetering devices, and replacement registers equipped with or without telemetering devices. As such, the term register is considered equivalent to AMR device in this document.

3.0 References

4.0 Terminology

Automatic meter reading device

An automated telemetering device which receives and stores measurement data from a source meter and transmits the data to a remote location at predetermined intervals or on demand.

Register

A mechanical indicating device fitted to a diaphragm meter which records the meter's gas volume registration; also referred to as "index".

Comparative registration test

A comparative registration test performed on a new register prior to it being installed on a meter that is being retrofitted in situ with an automatic meter reading device. The purpose of this registration test is to validate that the register is functional and compatible with its intended host meter. The test can serve as a substitute for the "dial test" that is normally performed during a meter's verification or reverification.

Telemetering

The transmission of measurement information with the aid of intermediate means that permit the source electricity or gas meter information to be interpreted at a distance.

Note: In this definition, the term "intermediate means" is broad enough to include hard-wired or wireless techniques for transmitting measurement data from the source meter.

Telemetering device

A device used in a telemetering system to duplicate the register reading of a source meter.

5.0 Background

Measurement Canada (MC) has approved various models of telemetering devices designed for use on diaphragm meters. Where a diaphragm meter is to be retrofitted in service with an approved mechanically coupled AMR device (i.e. an AMR device designed to be driven by the host meter's volumetric output drive mechanism) or replacement register, the installation process usually requires breaking the verification seal(s) on the meter's register cover in order to remove the register cover and the register. Breaking the verification seal(s) on a gas meter for this purpose and then resealing the meter without reverification is permitted under subsection 3(2) of the Electricity and Gas Inspection Regulations, provided that the AMR device or register installation is performed by an accredited meter verifier or an MC inspector.

When a mechanically coupled AMR device or register is installed on a diaphragm meter, unintended effects on the meter's accuracy can occur in both the short term and the long term if the AMR device or register is not properly installed or is not compatible with its host meter. Since these potential effects on meter performance cannot be detected or measured on meters while they are installed in service, MC requires that accreditation applicants evaluate their proposed device installation procedures prior to seeking accreditation to retrofit diaphragm meters in service with an AMR device or replacement register.

To assist contractors in performing this evaluation, MC has developed model procedures P-G-03 and P-S-01, which may be used to conduct the required paired difference experiments. These procedures require that accuracy tests be conducted on a representative group of sample meters both before and after they are retrofitted. MC has also developed a computer spreadsheet that may be used to perform the statistical calculations and to analyze the data generated by the paired difference experiment described in P-S-01. The computer spreadsheet may be obtained upon request from the local MC office.

6.0 Policy

Organizations (applicants) seeking accreditation to install mechanically coupled AMR devices on diaphragm gas meters in service shall comply with the following requirements.

6.1 Procedure for the installation of automatic meter reading devices and replacement registers

Appropriate quality assurance (QA) procedures shall be developed that incorporate the device manufacturer's recommended procedures for the installation of the device. These QA procedures shall include the instructions needed to address any problems identified as a result of performing the paired difference experiments described below.

6.2 Paired difference experiments

6.2.1 A paired difference experiment shall be conducted for each intended AMR device/meter or register/meter model combination, using either the model procedures identified in section 3 or alternate procedures established or referenced by applicants in support of their conclusion that their proposed QA procedures for installing the device will not adversely affect the performance accuracy of the intended host meters.

6.2.2 As an alternative to conducting their own paired difference experiment(s), applicants may make reference to applicable test results for paired difference experiments conducted by other contractors, provided the applicant has concluded that the sample meters used in those referenced experiments are representative of their own target meter population(s), and the applicant's QA procedures for AMR device installation are identical to those used in the referenced paired difference experiment(s).

6.2.3 MC will not make acceptance decisions on the test results obtained from a paired difference experiment or the procedures used for conducting the experiment. Accreditation applicants will however be required to provide MC with an attestation that they have an empirical basis for their conclusion that their proposed QA procedures are appropriate for application to the target meter population(s) which they intend to retrofit. Applicants are required to maintain a record of paired difference experiment test results which demonstrate that the subject meters will not be adversely affected as a result of using the proposed QA procedures and make the test results available to MC upon request.

6.3 Replacement register

6.3.1 If a meter's original register is being replaced with a new register during the device installation process, the new register shall be one which has already been subjected to a register examination, and shall bear a status indicator (i.e. a marking or label) which denotes that it passed the register examination.

6.3.2 The register examination may be conducted either by the accredited meter manufacturer, an accredited meter service organization, or an accredited contractor, and shall be performed in accordance with the QA procedures of the accredited organization.

6.4 Register cover sealing

6.4.1 Register covers on diaphragm meters are required to be sealed or resealed after installation.

6.4.2 Where a retrofitted meter no longer possesses a verification seal with markings that provide an indication of the meter's original seal year (i.e. the year in which the meter was last verified or reverified), actions must be taken to ensure that the meter's original seal year continues to appear on the meter while it is in service.

7.0 Revisions

7.1 The purpose of this revision is to include mention of the availability of a computer spreadsheet that may be used to perform the statistical calculations required by P-S-01.

7.2 The purpose of revision 3 was to amend the document's scope (section 2) to clarify that the installation of replacement registers on diaphragm meters in service is considered equivalent to the installation of an AMR device on these same meters.

7.3 The purpose of revision 2 was to:

  1. Clarify the scope of the bulletin.
  2. Insert the numbers of the model procedures listed in section 3.0.
  3. Explain that model procedures P-G-03 and P-S-01 are being provided as evaluation tools for use by gas contractors to enable them to conduct the required paired difference experiments and make their own acceptance decisions on the test results.
  4. Recognize the use of alternative procedures for conducting paired difference experiments.
  5. Allow gas contractors to make reference to paired difference experiments that were performed by other contractors in support of their application for accreditation to install AMR devices on diaphragm meters in service.
  6. Amend the requirements for pretesting replacement registers.
  7. Add a requirement to reseal the meter's register cover after installation of the AMR device.
  8. Add a requirement for ensuring that each retrofitted meter continues to bear a marking which identifies the calendar year in which the meter was last verified.

7.4 The purpose of revision 1 was to remove requirements identified under the Government of Canada's Paper Burden Reduction Initiative, make grammatical revisions, clarify that only new registers require pretesting, and reformat the bulletin to conform with MC's current template for bulletins.

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